AtCoder Beginner Contest 002 Solutions

Problem A: Maximum Value Given two positive integers as input, output the larger value. Solution Simply compare the two values and output the maximum. #include <bits/stdc++.h> using namespace std; int main() { int a, b; cin >> a >> b; cout << max(a, b) << endl; return 0; } Problem B: Remove Vowel ...

Posted on Wed, 20 May 2026 21:00:00 +0000 by HostingTrade

Efficient Interval Merging for Range Exclusion Calculations

Problem A: Textbook Availability Decision #include<iostream> using namespace std; int main() { ios_base::sync_with_stdio(false); cin.tie(0); int regular, extra, discount; cin >> regular >> extra >> discount; double direct_cost = regular + extra * 0.5; double discounted_cost = (regular ...

Posted on Wed, 20 May 2026 20:28:03 +0000 by wata

Linked List Operations in JavaScript: Node Swapping, Removal, Intersection, and Cycle Detection

Swapping Adjacent Nodes in Linked List This algorithm swaps every two adjacent nodes in a linked list using a dummy head approach for consistent handling. Key implementation details: Use a dummy head node to simplify edge cases Maintain current pointer before the pair being swapped Careful manage temporary references during swapping Ensure loo ...

Posted on Wed, 20 May 2026 20:24:22 +0000 by Pedro Sim

Introduction to Segment Trees

What is a Segment Tree? A segment tree is a binary tree-based advanced data structure that supports flexible range operations. Unlike a Fenwick Tree (Binary Indexed Tree) which is limited to simple point update/range query use cases, segment trees can handle range updates with point queries, and even full range updates with range queries effici ...

Posted on Wed, 20 May 2026 07:33:16 +0000 by Stryks

Grouped Knapsack Problem: 2D and 1D Dynamic Programming Approaches

Problem Statement Given n items, each with weight weight[i], value value[i], and group index group[i], pack them in to a knapsack with maximum capacity W. Each group can contain at most one item. Find the maximum total value. Solution 1: Two-Dimensional DP Array This is a classic grouped knapsack problem. First, we need to process all items sim ...

Posted on Wed, 20 May 2026 05:18:47 +0000 by jeffshead

Solutions for AtCoder Beginner Contest 319

Legendary Players A direct mapping from player handles to their respective ratings is required. A hash map provides an efficient and clean way to resolve this without writing multiple conditional statements. #include <iostream> #include <string> #include <unordered_map> using namespace std; int main() { unordered_map< ...

Posted on Tue, 19 May 2026 22:20:14 +0000 by drawmack

Solving Codeforces 1692F: 3SUM Problem Analysis

Approach 1: Brute Force Method A straightforward solution involves checking all possible combinations of three indices using nested loops. This approach iterates through every possible triplet (i, j, k) in the array. The time compleixty is O(T × N³), which is impractical given the constraint 3 ≤ n ≤ 2 × 10⁵. This method would exceed time limits ...

Posted on Tue, 19 May 2026 02:57:21 +0000 by blurredvision

Linked List Algorithms: Pair Swapping, Node Removal, Intersection Detection, and Cycle Identification

24. Swap Nodes in Pairs Problem Link: LeetCode 24 Solution: This problem involves swapping adjacent nodes in a linked list in pairs. A dummy head node simplifies edge case handling, such as when the list has only one or two nodes. struct ListNode { int val; ListNode *next; ListNode(int x) : val(x), next(nullptr) {} }; class Soluti ...

Posted on Tue, 19 May 2026 01:54:15 +0000 by Buttero

Base Number Conversion Algorithms and Implementation

Problem B: Arbitrary Base Conversion This code converts a number from one arbitrary base to another. Implementation #include <stdio.h> #include <string.h> // Convert from base `src_base` string `src_num` to decimal integer. int convert_to_decimal(int src_base, const char *src_num) { int result = 0; int place_value = 1; ...

Posted on Mon, 18 May 2026 01:51:55 +0000 by thebluebus

Unbounded Knapsack Dynamic Programming: Combinations vs Permutations

Unbounded Knapsack ProblemIn the classic 0/1 Knapsack problem, each item can be selected at most once. The Unbounded Knapsack problem modifies this constraint: each item can be chosen an unlimited number of times. Consider a knapsack with a maximum capacity of 4, and the following items:ItemWeightValueA115B320C430The core difference in implemen ...

Posted on Sun, 17 May 2026 17:18:17 +0000 by bbristow